1994 Chevrolet Other auto a/c

had bad clutch on ac compressor.replaced compressor with clutch,drier and filter.pulled vacuum on system.checked ok,no apparent leaks.new high pressure switch installed.tuned on a/c switched to high,blows fuse.unplugged high pressure switch connector fan stays on ,no problem.turn off a/c ,plug in high pressure switch and unplug low pressure connector,turn on a/c /fan stays on does not blow fuse.turn off a/c plug in low pressure connector blows fuse.jumper low pressure connector/turn on ac blows fuse.has one can of freon charge